JPH0894477A - Pipe leak inspection device - Google Patents

Abstract

(57) [Summary] [Purpose] To perform leak inspection of welded joints of pipes. A half-split type cylindrical transparent case 1 which covers a pipe 6 to form an airtight chamber between the pipe 6 and a suction device 4 which is connected to the case 1 to make a base airtight chamber a negative pressure. The water supply pipe 5 connected to the case and the case 1
The packing material 3 is attached to the outer peripheral portion of the inner surface. Case 1
A negative pressure is applied to the inside to absorb water, and the presence or absence of bubbles from the welded joint is visually inspected through the case to perform a leak inspection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak inspection device for inspecting a pipe for leaks.

[0002]

2. Description of the Related Art Applicants have previously used, as shown in FIGS.
An apparatus for inspecting the welded joint (61) of the pipe (6) for leakage has been proposed (Japanese Patent Application No. 53-28032). This is a welded joint
A transparent case (7) partially airtightly covering the (61) is attached to the suction tube (7).
It is configured by connecting 1).

In the leakage inspection, first, soap water is applied to the welded joint portion (61), the case (7) is covered and suction is carried out from the suction pipe (71). If the airtight chamber (8) formed between the case (7) and the pipe wall becomes negative pressure and there is a leak in the welded part (61), the air in the pipe is the airtight chamber (8) of the case (7). It is possible to detect leakage of the welded portion by visually observing that soapy water is foaming at this time through the transparent case.

[0004]

In the above device, in order to inspect the entire circumference of the welded joint portion (61), the positions to which the case (7) is applied must be sequentially shifted, and the same operation must be performed.
Due to the unevenness of the welded part, it becomes difficult to adhere the entire circumference of the opening edge of the case (7) to the tube surface, and it is difficult to maintain the vacuum inside the case (7), and the vacuum pump must be operated each time, which is troublesome. It was The applicant tried to suction the inside of the case by forming the case into a cylindrical shape, dividing the case into two, and making a round around the welded joint of the pipe to cover the case.

However, in the case of the two-part structure, it is difficult to maintain airtightness between the joints of the cases and the pipe wall.
Further, while the case was set in the pipe, the soapy water applied to the welded joint portion dripped off, and an accurate inspection could not be performed. As a result of diligent efforts, the applicant has ensured that the case itself and the airtightness between the case itself and the tube wall are reliably maintained, and that they can be easily attached to and detached from the tube, and that the part to be inspected of the tube is immersed in water, and We have completed a device that can realize leakage inspection, and will clarify it below.

[0006]

SUMMARY OF THE INVENTION A pipe leakage inspection apparatus according to the present invention comprises:
A cylindrical transparent case (1) covering the pipe (6) so as to form an airtight chamber (8) with the pipe, and a negative pressure in the airtight chamber (8) connected to the case (1). The case (1) is composed of a suction device (4) and a water supply pipe (5) connected to the case (1). The case (1) is a pair of half halves in which a cylindrical body is halved within a plane including an axis. The case (11) (11a) is openably and closably connected so as to form a cylindrical body in a closed state, and positioning means for holding the cylindrical body at the free ends of the two half-divided cases (11) (11a). 2) is provided, and a soft packing material (3) is attached to the inner surfaces of both half cases (11) (11a) around the outer peripheral edge, and the packing material (3),
The airtight chamber is the part surrounded by the half case (11) (11a) and the pipe wall.
(8), and the vertical packing material (31) extending along the axial direction of the case has grooves (32) (3) for communicating adjacent airtight chambers (8) (8).
2a) is opened, and the suction device (4) is connected to the pipe (41) connecting the case (1) and the vacuum pump (42) to the vacuum tank (43) and the vacuum tank (43) and the case (1). A sluice valve (44) is provided between the water supply pipe and the water supply pipe, and a sluice valve (51) is provided in the water supply pipe (5).

[0007]

[Operation and effect] The case (1) is opened and the inspection part of the pipe (6) is covered, and the case (1) is closed and sealed substantially by the positioning means (2). The tip of the water supply pipe (5) is immersed in the water tank (52), and the sluice valve (51) on the water supply pipe (5) is closed. Operate the vacuum pump (42) with the sluice valve (44) on the conduit (41) connecting the case (1) and the vacuum pump (42) closed, and bring the vacuum tank (43) to a state close to vacuum. To do.

The sluice valve (44) on the conduit (41) is opened. Case
The inside of (1) suddenly becomes negative pressure, and it is in a state of being tightened by vacuum pressure. When the water supply valve (51) is opened, the water in the water tank (52) is sucked into the case (1) through the water supply pipe (5). When the water level rises until the inspection part of the pipe is completely submerged in water, the sluice valve (51) on the water supply pipe (5) is closed.

If there is a leak in the inspection portion of the pipe, the air inside the pipe will enter the negative pressure case (1), and bubbles will be generated from the leak portion at this time. Visually see the generation of bubbles through the transparent case (1),
Detects defective parts. As described above, an accurate inspection can be performed because the inspection is performed depending on the presence or absence of bubbles while the inspection portion of the pipe is immersed in water.

Further, the case (1) is a half case (11) (11
a) openably and closably connected, and positioning means at the free ends of each other
Since it has (2), it can be easily attached to and detached from the pipe (6). Further, since the vacuum tank (43) is provided in the pipe line (41) connecting the case (1) and the vacuum pump (42), the vacuum pump (42) is operated regardless of whether the sluice valve (44) is opened or closed, and the vacuum pump (42) is operated. Tank (43)
Since the inside can always be maintained in a state close to a vacuum, the case (1) can be sealed by a sudden negative pressure, and even if there are many inspection points, the case (1) can be transferred to the inspection points of the pipe (6) one after another. The inspection work can be performed efficiently by changing the attachment.

[0011]

EXAMPLE FIG. 4 shows the inspection part of the pipe (6), and in the example, the case (1) set in the welded joint part (61) of the welded joint pipe (6),
The piping diagram of the suction device (4) which makes a negative pressure in the case (1) is shown. The suction device (4) includes a case (1) and a vacuum pump (42).
A transparent small tank (40), a gate valve (44), a filter (45), a vacuum tank (43) in order from the case (1) side to a pipe line (41) connecting with
Is provided.

A vacuum switch (46) and a vacuum gauge (47) are provided between the vacuum tank (43) and the vacuum pump (42). A drain valve (48) is connected to the tank (43). The vacuum switch (46) detects the vacuum pressure in the conduit (41) and automatically turns the vacuum pump (42) on and off, and the vacuum tank (4
The inside of 3) is maintained at the vacuum pressure within the set range.

The transparent small tank (40) prevents water from flowing into the vacuum tank (43) when the pipe (6) is placed horizontally. A sluice valve (49) is connected to the transparent small tank (40), and after the inspection is completed, the sluice valve (49) is opened to communicate the pipe line (41) with the atmosphere, as described later, and the case ( 1) The water inside can be quickly discharged.

The case (1) is, as shown in FIGS. 1 and 2, a pair of half-split cases in which a cylindrical body is split in half within a plane including an axis.
(11) It is formed by (11a). Half Case (11) (11a)
Is made of a resin such as acrylic resin to be a transparent body, and handles (19) and (19) are provided at the center of the outer surface of the transparent body.

At the four corners of the outer surface of the two half cases (11) and (11a),
Positioning blocks (14) and (17) are provided in a protruding manner. Each block (14) of one half case (11a) has a cylindrical case
A fitting groove (13) is opened in a plane orthogonal to the axis of (1),
Further, a shaft insertion hole (15) is opened orthogonally to the fitting groove (13). Each block (17) of the other half case (11) is provided with a fitting piece (16) that can be fitted into the fitting groove (13),
A shaft insertion long hole (18) is formed in the fitting piece (16).

By fitting the fitting groove (13) and the fitting piece (16) of the two half cases (11) and (11a), both blocks are provided on the opening and closing center side of the half cases (11) and (11a). (14) (17) shaft insertion hole (15) and long hole
Fit the pivot (20) in series on (18), and split the half case (11) (11a)
It is supported by opening and closing and extending and contracting for the long hole (18). On the free end side of the half case (11) (11a), the block (14) (17)
A positioning means (2) is constructed by inserting a positioning shaft (21) into and out of the shaft insertion hole (15) and the elongated hole (18) in series.

In the embodiment, both the pivot shaft (20) and the positioning shaft (21) have a large diameter grip portion (22) at one end, and a screw portion at the tip of the shaft.
(23), and the tip screw part (23) is screwed into the block (14) to prevent it from coming off. Axis (20) and positioning axis
Loosen (21) and remove it from the shaft insertion hole (15) and long hole (18),
The case (1) can be separated into two half cases (11) (11a).

A soft packing material (3) is attached to the outer circumference of the inner surface of each half case (11) (11a) over the entire circumference. The packing material (3) is made of silicon resin and has a thickness of about 15 mm and a width of 20-
It is formed into a 25 mm thick transparent or semi-transparent strip and circulates seamlessly along the contour of the half cases (11) (11a).

When the case (1) is closed, the packing material (3)
The vertical packing material (31) slightly protrudes from the end surface of the half case (11) (11a) so as to be pressed closely to the adjacent vertical packing material (31). Further, as shown in FIG. 2, the outer end surface of each vertical packing material (31) is an inclined surface (31a) (31a), and when the case (1) is closed, the vertical packing material (31) (31) A wedge-shaped gap in which the inside gradually expands is generated. Further, as shown in FIG. 3, the packing material (3) has an inclined surface (30a) whose surface contacting with the pipe is inclined inward toward the inside. Due to the inclined surfaces (30a) and (31a) of the packing material (3), the case (1) can be covered in an airtight state even if there is an error in the outer diameter rod of the tube.

The vertical packing material (31) of the packing material (3) has the same height position as the adjacent vertical packing material (31), and in the embodiment, the upper and lower parts and the central portion of the vertical packing material (31). Grooves (32) and (32a) are opened at three locations. When the case (1) is closed by surrounding the pipe (6), the airtight chambers (8) (8) inside the packing materials (3) (3) of the two half-divided cases (11) (11a) are Groove (32) (3
Communicate through 2a). The groove (32a) in the central portion is formed with a width and a depth such that the welded joint portion (61) between the welded joints can be fitted with a margin.

On the inner surface of the half case (11) (11a), the inner side of the packing material (3) is in close contact with the packing material (3) and the transparent inner wall (1
0) is provided so as to project integrally with the half case or to be fixedly adhered by a transparent adhesive. The protruding height of the transparent inner wall (10) is
It only reaches the groove bottom of the vertical packing material (31) and does not hinder the air flow through the grooves (32) (32a) between the half cases (11) (11a).

The transparent inner wall (10) is a soft packing material.
It maintains the shape of (3) and maintains the airtightness of the half cases (11) and (11a). That is, the silicone resin packing material (3) is replaced with the acrylic resin half case (11) (11a).
Since it is technically impossible to fix it to the adhesive state, the inner peripheral surface of the packing material (3) is brought into close contact with the outer peripheral surface of the inner wall (10), so that the packing material (3) and the half case (11) ( 11a)
The airtightness of the packing material (3) is enhanced, and the positioning of the packing material (3) is defined. If the airtight chamber (8) between the pipe wall and the case (1) becomes a negative pressure, the packing material (3) will be pulled inward, but the more it is pulled inward, the tighter the airtightness with the inner wall (10) becomes. The airtightness between the packing material (3) and the inner wall (10) is guaranteed even if the packing material (3) is not adhesively fixed to the half case (11) (11a).

Of the two half-split cases (11) (11a), the pipe line (41) of the suction device (4) is provided at the upper part of the outer surface of one half split case (11a).
, And a water supply pipe (5) is connected to the lower part of the outer surface. The water supply pipe (5) is provided with a sluice valve (51).

Next, a method of using the above inspection device will be described. Open the case (1) to open the weld joint (6) of the weld joint pipe (6).
The case (1) is closed after going around 1), and the positioning means (2) is used for positioning. At this time, the vertical packing material (31) of the case (1)
Fit the welded joint (61) into the groove (32a) in the center of the
Set the case (1) so that there is no gap between (3) and the pipe wall, and set the airtight chamber (8) between the half case (11) (11a), the packing material (3) and the pipe wall. ) (8) is formed.

The tip of the water supply pipe (5) is immersed in the water tank (52), and the sluice valve (51) on the water supply pipe (5) is closed. Pipe line (41) connecting the case (1) and the vacuum pump (42)
The vacuum pump (42) is operated with the upper sluice valve (44) closed to bring the vacuum tank (43) to a state close to vacuum. The vacuum switch (46) linked to the vacuum tank (43) automatically turns the vacuum pump (42) on and off, and the inside of the vacuum tank (43) is constantly maintained at around 550 mmHg.

The sluice valve (44) on the conduit (41) is opened. Case
The inside of (1) suddenly becomes negative pressure, and it is in a state of being tightened by vacuum pressure. The case (1) of the embodiment is a half case (11) (11a).
Since it can be expanded and contracted by the length of the long hole (18) of the connecting part of the case (1)
When a tightening force is applied to the case (1), the diameter of the case (1) is reduced, and the packing material (3) can be effectively pressed against the pipe wall.

Further, the packing material (3) has an inclined surface (30a) whose surface contacting the pipe is inclined inwardly low, and the outer end surface of each vertical packing material (31) is an inclined surface (31a). For,
Due to the tightening force acting on the case (1), packing material
When the inclined surface (30a) of (3) presses the pipe wall and the inclined surfaces (31a) (31a) of the adjacent vertical packing materials (31) (31) press each other, the packing (3) is easy. Elastically deforms to tightly come into close contact with the mating member, further enhancing airtightness. When the pressure in the case (1) becomes negative, the water supply pipe (5) is opened and the water in the water tank (52) is sucked into the case (1). If the water level rises until the welded joint (61) of the pipe is completely submerged in water, the water supply pipe (5)
Close the upper sluice valve (51).

If there is a leak in the welded joint portion (61) of the pipe, the air inside the pipe enters the negative pressure case (1), and at this time, bubbles are generated from the leaked portion. The generation of bubbles can be visually observed through the transparent case (1) to detect a defective portion. As described above, an accurate inspection can be performed because the inspection is performed depending on the presence or absence of bubbles while the inspection portion of the pipe is immersed in water.

When the case (1) is set in the pipe (6) and the inside of the case is made a negative pressure, the soft packing material (3) of the half case (11) (11a) is pulled inward, In the embodiment, the inner wall (10) adhered and fixed to the half case (11) (11a) exists inside the packing material (3), and the packing material (3) is stronger and closer to the inner wall (10). The airtightness is improved.

The packing material for the half case (11) (11a)
When mounting (3), the four thick strip-shaped packing materials formed separately from the half case (11) and (11a) are attached to each half case (11).
A frame-shaped packing material that is adhered to the outer circumference of the inner surface of (11a)
Although it is conceivable to bond (3) to the half case (11) (11a), the packing material (3) made of silicon resin and the half case (11) (11a) made of acrylic resin are bonded. The adhesive for this is not in practical use at present and is unreasonable.

In the packing material (3), grooves (32) (32a) are formed in the vertical packing materials (31) (31) that are adjacent to each other and communicate with each other in both half case cases (11) (11a). Because it was made half of the case
All you have to do is pipe to (11), which simplifies the device.
In addition, when opening and closing the case (1), piping is formed only in one half case (11), compared with the case where piping is formed in both half cases (11) and (11a). Opening and closing the case (1) is easy.

The case (1) is a half case (11) (11
a) openably and closably connected, and positioning means at the free ends of each other
Since it has (2), it can be easily attached to and detached from the pipe (6).

When the inspection of one place is completed, the sluice valve (44) of the pipe line (41) is closed, the sluice valve (49) is opened, and the inside of the case (1) is communicated with the atmosphere. The sluice valve (51) of the water supply pipe (5) is opened, and the water in the case (1) is collected in the water tank (52). If water is sucked into the transparent closed tank (40), the gate valve (49)
The water in the tank (40) can be discharged through. Remove the case (1), set it in the next welded joint, and perform a leak inspection by the same procedure as above.

The present invention is not limited to the configuration of the above embodiment, and various modifications such as leakage of a horizontal pipe can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a case is opened.

FIG. 2 is a transverse cross-sectional view with a case closed.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a piping system diagram.

FIG. 5 is an explanatory diagram of a conventional example.

6 is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 (1) Case (11) Half case (11a) Half case (2) Positioning means (3) Packing material (31) Vertical packing material (32) Groove (4) Suction device (42) Vacuum pump (43) Vacuum Tank (44) Gate valve (5) Water supply pipe (51) Gate valve

Claims (1)

[Claims] 1. A cylindrical transparent case (1) which surrounds a pipe (6) and forms an airtight chamber (8) with the pipe, and the case.
Suction device (4) connected to (1) to make airtight chamber (8) a negative pressure
And a water supply pipe (5) connected to the case (1), the case (1) is a pair of half-split cases (11) (11) 11a) is openably and closably connected so as to form a cylindrical body in a closed state, and positioning means (2) is provided for holding the cylindrical body at the free ends of the two half cases (11) (11a). Attach the soft packing material (3) around the outer peripheral edge around the inner surface of both half cases (11) (11a),
The part surrounded by the packing material (3), the half case (11) (11a) and the pipe wall is the airtight chamber (8), and the vertical packing material (31) extending along the axial direction of the case is adjacent to the air gap. Grooves (32) (32a) communicating the closed chambers (8) (8) are opened, and the suction device (4)
Is provided with a vacuum tank (43) and a sluice valve (44) between the vacuum tank (43) and the case (1) in a pipe line (41) connecting the case (1) and the vacuum pump (42). , Water supply pipe (5) with sluice valve
(51) Pipe leak inspection device.